1. Field of the Invention
The present invention is in the technical field of crop protection compositions which can be used against unwanted vegetation, for example by the pre-sowing method (with or without incorporation), by the pre-emergence method or by the post-emergence method in sown or planted crop plants such as, for example, in wheat (durum wheat and common wheat), corn, soybeans, sugar beet, sugar cane, cotton, rice (planted or sown under upland or paddy conditions using indica or japonica varieties and also hybrids/mutants/GMOs), beans (such as, for example, bush beans and broad beans), flax, barley, oats, rye, triticale, oilseed rape, potatoes, millet (sorghum), pasture grass, greens/lawns, in fruit plantations (plantation crops) or on non-crop areas (for example squares of residential areas or industrial sites, rail tracks). In addition to the single application, sequential applications are also possible.
It relates to a herbicide combination comprising at least two herbicides and to their use for controlling unwanted vegetation, in particular a herbicide combination comprising N-{2-[4,6-dimethoxy-(1,3,5)triazine-2-(carbonyl- or -hydroxymethyl)]-6-halophenyl}difluoromethanesulfonamides or their N-methyl derivatives and/or their salts, hereinbelow also referred to as “dimethoxytriazinyl-substituted difluoromethanesulfonylanilides”, and to herbicidally active compounds from the group of the pyrimidines.
2. Description of Related Art
It is known that cyclicly substituted sulfonamides have herbicidal properties (for example WO 93/09099 A2, WO 96/41799 A1). These also include the phenyldifluoromethanesulfonamides, which are also referred to as difluoromethanesulfonylanilides. The last mentioned compounds are, for example, phenyl derivatives which are mono- or polysubstituted, inter alia by dimethoxypyrimidinyl (for example WO 00/006553 A1) or dimethoxytriazinyl and also a further halogen substitution (for example WO 2005/096818 A1, WO 2007/031208 A2).
However, specific compounds from the group of the N-{2-[4,6-dimethoxy-(1,3,5)triazine-2(-carbonyl- or -hydroxymethyl)]-6-halophenyl}difluoromethanesulfonamides, as described in WO 2005/096818 A1, and their N-methyl derivatives, as described for the first time in WO 2006/008159 A1 in connection with fungicides and in WO 2007/031208 A2 and JP 2007-213330 (unpublished) as herbicides, are not entirely satisfactory in all respects with regard to their herbicidal properties.
The herbicidal activity of the dimethoxytriazinyl-substituted difluoromethanesulfonylanilides against harmful plants (broad-leaved weeds, weed grasses, Cyperaceae; hereinbelow collectively also referred to as “weed”) is already at a high level, but depends in general on the application rate, the formulation in question, the harmful plants to be controlled in each case or the spectrum of harmful plants, the climatic and soil conditions and the like. Further criteria in this context are duration of action, or the breakdown rate, of the herbicide, the general crop plant compatibility and the speed of action (more rapid onset of action), the activity spectrum and behaviour toward follower crops (replanting problems) or the general flexibility of application (control of weeds in their various growth stages). If appropriate, changes in the susceptibility of harmful plants, which may occur on prolonged use of the herbicides or in limited geographical regions (control of tolerant or resistant weed species) may also have to be taken into account. The compensation of losses in action in the case of individual plants by increasing the application rates of the herbicides is only possible to a certain degree, for example because such a procedure reduces the selectivity of the herbicides or because the action is not improved, even when applying higher rates.
Thus, there is frequently a need for targeted synergistic activity against specific weed species, weed control with better overall selectivity, generally lower amounts of active compounds used for equally good control results and for a reduced active compound input into the environment to avoid, for example, leaching and carry-over effects. There is also a need for developing one-shot applications to avoid labor-intensive multiple applications, and also to develop systems for controlling the rate of action, where, in addition to an initial rapid control of weeds there is also a slower, residual control.
A possible solution to the problems mentioned above may be to provide herbicide combinations, that is mixtures of a plurality of herbicides and/or other components from the group of the agrochemically active compounds of a different type and of formulation auxiliaries and additives customary in crop protection which contribute the desired additional properties. However, in the combined use of a plurality of active compounds, there are frequently phenomena of chemical, physical or biological incompatibility, for example lack of stability of a joint formulation, decomposition of an active compound or antagonism in the biological activity of the active compounds. For these reasons, potentially suitable combinations have to be selected in a targeted manner and tested experimentally for their suitability, it not being possible to safely discount a priori negative or positive results.
Mixtures of non-N-methyl derivatives of the compounds mentioned above are known in principle (for example WO 2007/079965 A2); however, their effectiveness in mixtures with other herbicides has only been confirmed in individual cases for dimethoxypyimidinyl-substituted phenyl derivatives. In addition, there are also mixtures of selected N-methyl derivatives of the compounds mentioned above with some combination partners (PCT/EP2008/000870, unpublished).